1. Field of the Invention
This invention broadly relates to machines for automatically making small pieces of ice. More particularly, it concerns improved forms of evaporator units comprising a grid of ice-forming molds for such machines.
2. Description of the Prior Art
The extensive use of ice pieces (so-called "ice cubes") for cooling of drinks, preserving food, etc., has created a sizeable market for machines that automatically make and store ice pieces in response to user demand. Typically, such machines comprise an evaporator unit wherein refrigerant is brought in indirect heat exchange with water recycled from a sump over an ice-forming surface. After a sufficient quantity of ice is formed, the resulting ice pieces are separated from the ice-forming surface, e.g., by momentarily heating the surface by reverse cycling of gas from the compressor unit. An ice making machine of this general type is disclosed, for example, in U.S. Pat. No. 2,997,861.
Some machines of this type are constructed so that ice pieces of various shapes may be produced, e.g., see U.S. Pat. No. 3,171,267. However, ice piece shape variation is not considered of much importance for automatic ice making machines and the present invention concerns machines that produce a single shape of ice piece, namely, pieces of substantially semi-cylindrical shape.
One of the problems in production and use of ice making machines is the construction of ice forming molds for the machines, e.g., see U.S. Pat. Nos. 3,075,365 and 3,736,767. Such molds must provide effieicent use of refrigerant, permit sanitary operation for the ice formation and allow ice pieces when formed to be easily harvested and stored ready for use. The present invention concerns improvements in the evaporator and ice molding sections of automatic ice making machines.